Biological Causes And Consequences Of Redox Reaction And Hydrogen Peroxide
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Free radicals are atoms/molecules that have unpaired electrons in their orbital structure. Free radicals are required for all living organisms for survival. In an organism, they are produced through highly conserved and important biological redox reactions. Redox reaction is a reaction that involves transfer of electrons between reductant and oxidant. Consequently, making biological process activated or inactivated.
Superoxide anion, hydrogen peroxide, hydroxyl radical, hypochlorous acid and hydroperoxide radical are examples of reactive oxygen species (ROS). Superoxide radical is produced during electrons leakage from the mitochondrial electron transfer chain (ETC). It is also produced during nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, xanthine oxidase and aldehyde oxidase reactions. The other reaction that generates superoxide is by inflammatory cells including neutrophills, eosinophills, monocytes, and macrophages during phagocytosis. Hydrogen peroxide is produced by superoxide dismutase (SOD) enzyme. Hydroxyl radical is the most reactive of all ROS. It is produced when hydrogen peroxide reacts with iron and this series of reactions involve Fenton and Haber-Weiss reactions. Hypochlorous acid is produced during myeloperoxidase action. Nitric oxide and peroxynitrite are the examples of reactive nitrogen species (RNS). Nitric oxide is converted to nitrate or nitritre molecule. When nitric oxide is reacted with superoxide, it turns into very